Transport conveyances such as aircraft are used for conveying freight as well as passengers. The same aircraft may, for example, operate during daytime as a passenger aircraft and as a freight conveyance during the night. For this purpose it is necessary that the change-over from a passenger aircraft to a freight conveyance and vice versa can be rapidly performed to assure the proper latching or lashing of freight items including the mounting and demounting of passenger seats. Thus, the freight loading systems must be constructed for a rapid change-over to be adaptable to different requirements.
Moreover, the freight items to be transported may have the most varied features. For example, standardized containers and pallets as well as unstandardized freight items must be transported. Unstandardized freight items include, for example bags lashed to a support such as a chipboard. Vehicles are another example of not standardized freight items that must be transported. The relative high weight of these freight items impose high requirements regarding the static and dynamic forces and moments that must be taken up by the structures of the loading floor and by the load lashing positions, each comprising an individual lashing device. It may also be required to satisfy special conditions for special missions such as the transporting of medical supplies and medical units. In addition to satisfying all strength and regulation requirements the change-over or retooling must be realized within a minimum of time by a minimum of service personnel.
Conventional systems use passenger seats mounted on pallets for carrying of passengers, whereby the pallets are secured to the loading floor. If the aircraft is to be used for transporting freight, the seat carrying pallets must be removed and conventional function elements or units must be made available for the freight transport. Such function elements or units include, for example lashing positions, roller units, latching or interlocking devices, guide rails and the like so that other pallets, containers or other freight items can be secured to the loading floor instead of the passenger seat carrying pallets.
It is conventional to mount seats and other load systems directly and alternatively to the loading floor. However, additional mounting possibilities are required for this purpose. Conventionally, mounting rails or lashing positions are provided as mounting interconnections in such a way that either passenger seats or the above mentioned function elements of the freight loading system can be secured to the loading floor. FIG. 1 shows such a system. Lashing devices with lashing rings are located in predetermined positions for lashing of freight items to the loading floor or deck. A multitude of lashing positions are usually provided and uniformly distributed at equal spacings on or in the loading floor in the loading space. The individual lashing device is generally secured directly to the aircraft supporting frame structure in order to be able to take up large forces and moments in all directions of space. If it becomes necessary that the lashing devices or lashing positions of a freight loading system must additionally be useful for the securing of other components or systems, the lashing devices must be either completely replaced or partially dismantled and supplemented. Such operations are time consuming and have the disadvantage that individual elements of the lashing devices can get lost.